The sebaceous glands, located under the skin near hair follicles, secrete a greasy or oily substance known as sebum. Sebum normally flows through the sebaceous duct and into the hair follicle and from there to the surface of the skin, where it is useful to lubricate the skin and hair. The largest sebaceous glands in humans are those which secrete sebum at the greatest rate and are located on the face, scalp and back. When the sebaceous glands operate to secrete the desired amount of sebum, the skin appears fresh and alive. When too little sebum flows, the skin becomes dry and tends to crack and wrinkle. When excessive sebum is secreted, a characteristic greasy appearance of the skin is observed. Excessively oily skin is a problem associated with adolescents and can result in acne, in which the duct of the follicle canal is hyperkeratinized, leading to the creation of sacks plugged with liquids and solids. In addition, the undesirable nature of oily films on the skin has an adverse effect on the appearance of women's cosmetics and makeup, often causing them to change color or shade.
Several methods have been proposed to collect and quantify the secretions from sebaceous glands. One such method and device is disclosed in U.S. Pat. No. 4,532,937 in which a microporous film is adhesively attached to the skin for absorbing sebum. After removal from the skin, the film contains surface patterns that can be compared to standards for determining the location and relative rate of secretion of sebaceous glands on the subject's skin. A device for observing the degree of dry skin is disclosed in U.S. Pat. No. 5,088,502.
A need has arisen for an improved device for collecting sebum to provide a highly visible indication of sebum absorption by a monitoring device.